1. Field of the Invention
The present disclosure relates to a latch relay and, more particularly, to a latch relay having consistency of performance by reducing a load variation applied to a movable contactor and maintaining a uniform operational distance of the movable contactor.
2. Background of the Invention
In general, a relay or an electromagnetic contactor is a type of an electric circuit switching device transmitting mechanical driving signal and a current signal using a principle of an electromagnet, which is installed in various industrial facilities, machines, and vehicles.
Among relays, in particular, a latch relay, also called a bi-stable relay, features that a switched state is maintained even energy is not supplied after an operation. The latch relay has a structure generally operated by a permanent magnet and a solenoid actuator.
A latch relay (Korean Patent Laid-Open Application No. 10-2014-0129420) devised and filed by the inventor of the present application is illustrated in FIG. 1.
The related art discloses a latch relay including a frame 110; a bobbin 120 installed in the frame 110 and having a coil 121 wound therearound; first and second yokes 130 and 135 coupled to both sides of the bobbin 120 and provided as magnetic bodies; a rotary mover 140 formed of a magnetic body and rotating in a clockwise direction or in a counterclockwise direction between head portions 132 and 137 of the first and second yokes 130 and 135; a transmission lever 150 having one end coupled to one side of the rotary mover 140 to make a vertical movement; and leaf spring 175 moved by the other end of the transmission lever 150 to cause the movable contactor 170 to be brought into contact with the first fixed contactor 160 or separate the movable contactor 170 from the fixed contactor 160, wherein a horizontal long hole 151 is formed in the transmission lever 150 and a shaft member 149 slidably coupled to the horizontal long hole 151 is provided on one side of the rotary mover 140.
In the related art, the movable contactor 170 is configured to be brought into contact with the fixed contactor 160 by the leaf spring 175. That is, the transmission lever 150 pushes up the leaf spring 175 having elasticity, generating a contact force, and here, a movable contact 172 is brought into contact with a fixed contact 162 using the generated contact force, thus exhibiting conduction performance. Here, the contact force greatly affects the conduction performance and is closely related to contact resistance (electromagnetic repulsion force).
However, in the related art latch relay, as the leaf spring is used for a long period of time, fatigue failure may occur in a material thereof to reduce contact force due to plastic deformation. Thus, an operational distance of the movable contactor may be reduced to degrade conduction performance or cause defective conduction. Also, variations occur in operational loads of the leaf spring during ON/OFF operations in terms of material characteristics, causing a problem in that operational characteristics thereof are different in the ON/OFF operations (i.e., when the latch relay is turned on or off). In addition, the leaf spring has a large load error by products and load variations regarding deformation, resulting in a degradation of consistency by products.